Effect of the commercial processing procedures on [14]C chlorpyrifos residues in soybean oil

ABSTRACT

Crude soybean oil extracted from grains treated with chlorpyrifos at a dose of 15 mg insecticide/kg seeds and stored for 30 weeks was subjected to different refining processes such as alkali treatment, bleaching, winterization and deodorization. The effect of the refining processes on the nature and magnitude of the originally present residues was investigated. The radioactive insecticide residues in crude oil and cake amounted to 9% and 65%, respectively, of original radioactive residues inside the seeds. A high percentage of the residues [50-55%] were removed during alkali treatment and bleaching steps. The C-activity in the crude stored soybean oil could be reduced by about 85% of radioactivity originally present in crude oil through simulated commercial processes locally used for oil refining. Refined soybean oil fortified with [14]C-chlorpyrifos had only 20% of the radioactivity originally present, mainly in the form of chlorpyrifos, and 3,5,6-trichloropyridinol in addition to desethylchlorpyrifos [in oil with aged residues]